The present invention relates to the manufacture of antimony oxide and to apparatus used to produce the same.
Antimony oxide is a fine white powder often used as a pigment and/or employed as an ingredient in fire-retardant compositions. Frequently, it is manufactured from antimony sulfide for burning a sulfide containing ore in air. The burning is conventionally accomplished in a direct fired kiln or furnace by supplying heat obtained from the combustion of a gaseous hydrocarbon fuel in air. Antimony oxide vapor so-produced is quenched by mixing it with cooling air to develop a finely divided solid or powdery material. The powdery material is separated from the combustion products and coolant air which both contain large quantities of sulfur dioxide albeit in a relatively low concentration. Removing the sulfur dioxide from the gaseous stream is difficult and costly and often times leaves the sulfur dioxide in a form which cannot be economically isolated.